I wasn't in Brussels, but you could feel David Cameron's frustration over the issue of bank bonuses from miles away.

The prime minister knows that it was not his public exhortation or the Treasury's private nudges or winks or even arm-twisting which stopped Stephen Hester's bonus.

It was instead a parliamentary motion tabled by the Labour Party. Mr Cameron called that "the luxury of opposition" and "headline grabbing" and paid Ed Miliband the ultimate compliment on naming him more than once in his news conference.

The PM insists that he is sticking to the rules drawn up by the last Labour government which properly keep ministers at arms length from the running of RBS.

He fears that undue interference could lead the bank's executives or even its whole board to walk away.

The problem is that Mr Hester is just one bonus amongst many yet to come. Some in the coalition - in both parties - are growing impatient at their apparent impotence in the face of the bankers' bonuses.